Fuse device



N, J. CONRAD Dec. 1, i931.

FUSE DEVICE Filed May 25, 1925 2 Sheets-Sheet 1 Dec. 1, 1931. N J CONRAD1,834,578

FUSE DEVICE Filed May 25, 1925 2 sheets-sheet 2 l foe 50 720 434ePatented Dee. 1, 1931 l UNITED STATES PATENT OFFICE NICHOLAS J. OONRAD,or WILII'ETTE, ILLINOIS, AssIGNon, BY IIESNE A'ssIGNImNTs, To scnwnrrznaa CONRAD, INC., or CHICAGO, ILLINOIS, A CORPORATION or mma- WAREApplication led May 25,

This invention relates to improvements in fuse devices and the like, andis a continuation in part of my prior application, Serial No. 631,263,filed April 1l, 1923, wl,1ich matured into Patent N o. 1,743,322, issuedJ anuary 14, 1930. l

While it is to be understood that the present invention is not limitedto a particular form of device, it relates more especially to fusedevices generally of the Schweitzer and Conrad type such as disclosed,for example, in Schweitzer and Conrad Patent No. 1,135,- 548, grantedApril 13, 1915.

In the present invention, I provide novel anti-vibration Spacer andvibration damping means for the movable fuse terminal means and for themeans for retracting or 'drawing said terminal means to open position.

The present invention further provides a' novel fuse element formechanically holding the movable terminal means set and which may berated to break the circuit at the desired point, novel means forassuring the rupture of the mechanical connection when the fuse blows, anovel mounting for the liquid director and novel means 'for attachingthe ends of the opening spring to the terminals of the fuse. v f

In Order to acquaint those Skilled in the art with the-manner ofconstructing and practicing my invention, I shall'now describe, inconnections with the accompanying drawings, certain speciic embodimentsof the invention.

Fig. 1 is a transverse section through a fuse device embodying myinvention, taken on the line 1-1 of Fig. 2;

Fig. 2 is a longitudinal section taken on the line 2,-2 of Fig. 1;

Fig. 3 is a transverse section taken on the line 3-3 of Fig. 2;

Ffg. 4 is a transverse section taken on the line 4-4 of Fig. 2;

Fig 5 is an enlarged fragmentary detail section taken on the line 5-5 ofFig. 1; d

Fig.\6 is a fragmentary elevational vview partially in section of thefuse element;

-Fig. 7 is a longitudinal section showing a moditied arrangement ofthe'fuse element;

FUSE DEVIUE 1925.y serial Ne. 32,740.

Fig. 8 is a transverse section taken on the line 8 8 of Fig. 7;

Fig. 9 is a longitudinal section through a modication Fig. 10 is afragmentary longitudinal section through the fuse of Fig. 9 afterblowing;

Fig. 11 is a top plan view of the fusev shown in Figs. 9 and 10 with thevent cap removed;

Fig. 12 is a transverse section taken on the line 12-12 of Fig. 9;

Fig. 13 is a longitudinal section through the upper arcing terminaltaken on the line 134-13 of Fig. 9; and

Fig. 14 is a side elevational view partially in section-of the lowerterminal' member.

The fuse illustrated in Figs. 1 to 6 comprises a hollow Sleeve or tube 5of insulating material. It may be cylindrical in form and of glass, asshown, or its form may be Otherwise as desired and it may be formed of.any

other suitable or preferred insulating mate# rial, such as for example,with bakelite.

A base 6 is secured 'upon the bottom of the tube 5 and secured upon theupBer or opposite end of the tube 5 is a ferrule 8. The

fiber impregnated base 6 and ferrule 8 are of metal, or othersuitableconducting material, and they form the fuse terminals and areconnectedor disconnected by the conducting parts within the tube 5. The base 6and ferrule 8 may be secured upon the tube 5 in the manner and by meansof the sealing means disclosed inf my hereinbefore referred toco-pending application, now Pat. No. r`1,743,322, or otherwise. Themeans there disclosed is in the nature of a non-drying cement which willnot harden or become brittle and it forms proper seals 10 between thetube 5 and base 6 at one end and between the tube 5 and ferrule 8- atthe other end.

The lower end of the base 6 is closed at 12 and it may have a taperedshoulder 13 for centering the tube 5 in the base 6 and providing minimumengagement between the lower end of the tube 5 and the base 6.` A boss14 projects upwardly from the center of the closed end or bottom 12 andis bored and internally threaded to receive the threaded end15 of thelower terminal member 16. The terminal member 16 is secured upon thelower end of the flexible stranded conductor or cable 17, whichconductor or cable extends longitudinally through the tube 5 and isconnected mechanically and electrically at its opposite or upper endtothe upper arcing terminal 25.

The terminal member 16 comprises a stud member or post, the lower end ofwhich is threaded into the boss 14 and above the boss the shank of thispost is secured in a collar 18 as by means of a screw 20. Above thecollar 18 the post is socketed as shown. The threads at the lower endmay be suiiciently larger than the portion of the post lying within thecollar 18 to additionally retain the terminal member againstdisplacement through the collar in one direction and the flaring orenlargement of the upper socketed end may additionally retain the postagainst displacement through the collar in the opposite direction.

The lower end of the stranded conductor 17 is inserted in the uppersocketed or boredout end of the terminal member 16 and union between thelower end of the strand and said terminal member may be produced bycrushing or pressing the wall of the socketed portion of the terminalmember inwardly at opposite sides to compress them upon the fibers ofthe stranded conductor and firmly and securely grip the conductor in theterminal member. A simple, eective and inexpensive mechanical andelectrical connection is thereby produced. The flat faces formed in theterminal member 16 thereby permit engagement by a suitable tool forscrewing the lower end of the terminal member into and out of the boss14, as more clearly shown in the embodiment illustrated in Figs. 9 to14.l At the same time, the swedging or crushing out of the upper end ofthe terminal member 16 forms the enlarged upper portion or retentionshoulders for preventing displacement of the terminal member through thecollar 18 in the opposite direction.

The upper end of the conductor 17 is secured in a movable or arcingterminal 25. vThe terminal member 25 comprises a stem or post, the lowerend of which may be bored out or socketed and crushed upon-the upperinserted end of the conductor 17 to form a good mechanical andelectrical connection therebetween, as described in connection with thelower terminal member 16. The upward- 1y extending shank of the terminalmember 25 projects through a collar -26 mounted thereon and securedagainst longitudinal movement and rotation relative thereto as by meansof a suitable screw 28. In addition, the crushing of the lower socketedend of the terminal member 25 enlarges the same and L additionallyprevents displacement in one direction through the collar. Above thecollar 26 the terminal member 25 may be enlarged or shouldered, ifdesired. v

Connected between the lower relatively stationary terminal member 16 andthe upper movable or arcing terminal member 25, for the purpose ofretractin'g or drawing said arcing terminal member 25 to open positionwhen the use blows, is a coil tension spring 30. The coil spring 3() iswound helically about the stranded conductor 17. The lower end of thespring 30 is wrapped about the collar 18 with one or more of its lowerconvolutions engaging with and held by pins 32 mounted in and projectingradially from the collar 18. This anchors the lower end of the springand prevents its pulling olii o the collar 18 when the spring isdistended. The screw 20 by being inserted below the lower convolution ofthe spring may Aprevent the lower end of the same from dropping or beingsprung down below the collar, thereby functioning with the pins 32 toanchor'the lower end of the spring against displacement in eitherdirection.

Like the lower collar 18, the upper collar 26 may be provided with oneor more radially projecting pins 35, preferably a pair arrangeddiametrically opposite. One or more of the upper convolutions of thespringBO is threaded around the pins 35 or wrapped circumferentiallythereabove whereby the upper end of the spring is anchored againstdownward displacement from the collar. The screw 28 may be arrangedabove the up-` per convolution of the spring to prevent upperdisplacement of the upper end of the spring, thereby cooperating withthe pins 35 to anchor the upper end of the spring against displacementfrom the collar 26 in either direction.

The upper ferrule 8 is provided with an internal flange 40, whichlia-nge 40 is formed with an annular shoulder 42 for the reception or"the vent cap 43, a second annular shoulder 44, and an upwardly flared ortapered surface 45. An annular ring 46 mounted in the ferrule 8 upon theshoulder 44, supports a washer y48 of bakelite or other suitablenon-conducting material. The washer 48 rests upon an annular shoulderextending inwardly at the lower end of the ring 46, and this washer 48has an axial opening 50. The upper end of the terminal member 2 5extends into the axial opening 50 and is held properly disposedcentrally within the tube 5 by engagement therein.

The arcing terminal 25 is held in its distended set position, as shownin Fig. 2,.and electrical connection is made between it and the terminalferrule 8 by the fuse element 52. As shown in Fig. 6, the fuse element52 comprises a fusible wire 53 which is enclosedy within anon-conducting strain sheath 54, or wrapped with a non-conducting strainelement, which is preferably of fishing cord, suitable fabric, orsuitable combustible material, although this, of course, may be varled.The fuse wire 53 is usually so line or its structureotherwise such thatit cannot take any of the tension or strain of the spring 30. The metalactually used in this vwire is nickelchromium, although this may bevaried. The wrapping or sheath 54 is therefore employed to withstand thestrain and give the fuse link 52 the necessary mechanical strength tohold the upper terminal and other parts in their set position, as shownin Fig. 2.

Intermediate or between the ends of the fuse link 52, the fusible wire53 is led out through the wrapping or mechanical strength impartingmeans 54 and is wrapped externally thereaboutat 55 to provide forelectrical contact with the terminal member 25. At the opposite ends ofthe link 52 the fusible wire 53 is also led out and wrapped externallyabout the wrapping or mechanical strength imparting material 54, asindicated at'56.

Diametrically through the upper end of the shank of the terminal member25 is an opening 60. The fuse link 52 is passed through this opening andis drawn taut and the exposed ends 56 of the fuse wire 53 are securedunder the heads of screws 62 threaded into the ferrule 8 atdiametrically opposite points in the flared or tapered surface 45. Theintermediate exposed portion 55 of the fuse wire 53 lies in the opening60 anden-l gages with the shank of the terminal member 25. This exposedportion 55 may be wrapped with tin-foil to assure good Vcontact with thearcing terminal 25 and to offer such mechanical protection for theexposed portion of the wire 53 as it may. The tin-foil wrapping isindicated at 65 in Figs. 2, 5 and 6.

By this construction of ther fuse element, the fuse wire 53 is connectedelectrically between the terminal member 25 and the ferrule 8, and atthe same time the wrapping 54 is connected mechanically between theterminal member 25 and the ferrule through the screws y 62 which providethe v electrical connection.

Consequently, the wrapping 54 holds the upper terminal 25 and otherparts set and the fuse wire 53 provides a sensitive electricalconnection between the upper terminal and the upper ferrule which may beaccurately rated to blow at the desired point.

en the fuse wire 53 is melt-ed or fused,

the wrapping 54 is subjected to the resulting arc. It at once burns andruptures the mechanical holding connection, freeing the terminal member25, whereupon said terminal member 25 is drawn downwardly to openposition by the spring 30, the liquid director or sprayer projecting astream of the arc extinguishing liquid 72 within the tube l5 upwardly,upon the space where the arc tends to form.

To assure burning' and rupture of the cord for wrapping 54, I mount aradial conducting adjacent screw 62 and it lies radially across thetop'of the ring 46 and washer 48 beneath one side of the fuse element 52 andits inner end may be turned down slightly/in the opening 50 toward theupper end of the shank of the Y terminal member 25. Consequently, whenthe fuse wire 53 blows, a more or less concentrated arc will be producedbetween the inner end of the linger 75 and the upper end of the terminalmember 25 immediately adjacent one side of the fuse element, so as tosubject the winding or strain element 54 thereof to this arc and assureburning and rupture of said element 54, to permit proper release andopening of the fuse.

The vent cap 43 has a marginal flange 78 and may be bulged centrally tobe sprung i tightly in place into the upper end of the ferrule 8 anddown upon the shoulder 42. .The vent cap with an application ofnondrying cement 79, such as disclosed in my hereinbefore referred toClo-pending application, now Pat. N o. 1 ,7 43,322, is pressed intoplace and the fuse hermetically sealed.

The sleeve or tube 5 contains an arc extinguishing liquid, the level ofwhich is prefalthough this may be varied as desired. The arcextinguishing liquid employed is preferably a derivative of a suitablehydro-carbon. It may be any one of the liquids disclosed in Patent No.1,319,907, dated October 28, 1919, or any preferred arc extinguishingliquid. The fuseelement 52 is plosion chamber in the ferrule 8 above thebakelite, lava, or other insulating washer 4S. Consequently, if the fuseblows on Very heavy overload or short-circuit, the resultin explosiveetl'ect is confined to the chamber above the washer 48 and below thesafety pressure Vent 43. The result is, that on shortcircuit or veryheavy overload, the vent cap blows off before any extensive pressure candevelop in the glass tube, and breakage of the glass tube is thusavoided. After the strain element 54 has burned or` ruptured, the washer48 is also free to rise and thus prevents any excessive pressure withinthe glass tube when the arcing terminal 25 is drawn down in the liquid.

The lower end of the ferrule 8 may be splayed on diametricallyopposite-sides to provide generally parallel flat contact surfaces andthe lower ferrule or base 6 may be similarly splayed to providesubstantially parallel flat contact surfaces 82. The ferrule 8 may besealed upon the`l tube 5 at 83 similar to the sealing of the base 6; andit also preferably has a tapered shoulder 84 for cenin a separate ex-Vyerably up to or just below thepwasher 48,

tering the tubeitherein and providing minikmum contact therewith. A

preferably three equally spaced, in which fit' pins of bakelite or othersuitable insulation 86. The pins 86 project radially, and as the screw85 is threaded in, the cone point thereof, forces said pins out intoengagement with suitable sockets or recesses in the liquid director 70,thereby securing the liquid director securely against axial movement orrotationon the terminal member 25. The liquid director may be of lava,bakelite or other suitable material and it tends to direct or squirtliquid upon the place where the are is drawn when the fuse blows. It is,in fact, a plunger fitting more or less closely in the tube 5 and havinga central opening, the lower end of which is flared or tapered outwardlyto the lower end of the director, as shown.

For the purpose of dam-ping vibration of the terminal member 25 andspacing and guiding the same, I provide a plurality of anti-vibrationspacing prongs or members 90. Three equally spaced about the terminal 25as shown, are preferable, and these prongs 90 may be of fiber, bakeliteor other suitable insulating material. Suitably secured upon the shankof the-terminal 25 is a washer 92 having a sharp edge orfrelativelysharp spaced portions along its edge which engage in notches 93 in theprongs 90. The prongs 90 are thereby fulcrumed upon the edge of thewasher 92 and their upper ends are tied together and normally contractedby means of an annularly arranged coiled spring 94, secured throughsuitable openings to the upper end of each prong. TheV contraction ofthe upper ends of the prongs spreads the, lower ends outwardly about thewasher-92 as a fulcrum into engagement with the tube 5, therebyyieldingly holding the terminal mem'- ber 25 properly positioned andyieldingly damping any vibration that occurs. This re-l lieves the fuseelement and other parts of the strain which would otherwise bey causedby such vibration. Each prong 90 is preferably provided with a pluralityof notches 93, as shown in Fig. 2, to adjust the .amount of projectionproduced by the spreading o'f the lower ends of the prongs, by changingthe position of the fulcrum along said prongs. In some instances,especially where the conductor 17 and spring 30 are relatively long, Ifind that it may be desirable to damp vibration of the spring 30 withinits length.

' For this purpose I provide within the length of the spring 30 a springvibration damper comprising an anti-vibration collar 96 which is alsopreferably of insulating material. EX-

tending radially through this, are three circumferentially spaced studsor anti-vibration pins 97. The inner reduced ends of these pins engagebetween convolutions ofthe spring 30 and hold the anti-vibration meansroperly positioned longitudinally thereof.

he outer ends of the pins 97 are headed and these headed ends engage thetube 5 and damp vibration of the spring 30. This anti-vibration meansmoves with the spring as it is distended or retracted and I find that itis desirable to place it at the center of the fuse spring, although ifadditional devices o'f this sort are desired, they may be spaced alongthe spring in any suitable manner.

In Figs. 7 and 8 I have shown the fuse link of the present inventionembodied in a device in which the upper arcing terminal comprises a pairof longitudinally spaced terminal members 100 and 102. rIhe opposingends, at least of these terminal members, are socketed or tubular. Thefuse link 103 is wrapped, as before, and the ends of the fuse wire ofsaid link are exposed, as before. The bared ends of the fuse link 103are inserted into the socketed ends of the terminal members 100 andI102, respectively, and said socketed ends are then crushed or fiattenedthereupon, as shown in Fig. 8. The fuse link 103 is thereby firmlygripped and mechanically held at its opposite end to the terminalmembers 100 and 102, and the exposed ends of the fuse wire make contactwith said termial members and connect the same electrica y. The wrappingof the fuse link is held -in the socketed ends of the terminal memberswith the fuse wire and takes the strain and mechanically sustains thelower terminal 102 from the upper terminal 100 when the fuse is set. Theadjacent ends of the terminal members'lOO and 102 and the uselink 103,are preferably confined in an envelope or covering preferably inthe formof a block or plug 105 of material such as cork.

In the embodiment of the invention shown in Figs. 9 to 14, the tube 5fhas sealed upon its lower end `a base 6 similar to the base 6 of theprevious embodiment, and sealed upon the upper end is the ferrule 8similar to the ferrule 8 of the previous embodiment.

In this embodiment the lower terminal 16 is formed similar to theterminal 16 of the previous embodiment, and is similarly provided with acollar 18. lThe opposite ends of the conductor 17 are, as before,secured in the upper socketed end of the terminal 16 and in the lowersocketed end of the upper arcing terminal 25 and is provided with someslack, even when the spring 30 is distended. The substantially parallelfiat faces 106 of this and the previous embodiment, are probably shownmore clearly in Figs. 9, 12 and 14. The screws 28 and 20 hold thecollars in place, or additionally hold them as before, and, as before,the opposite ends of the spring 30 are attached to the respectivecollars by reti-active effort means of radial pins 32 and 35', which maybe staggeredvto facilitate winding of the end convolution of the helicalcoil spring thereabout. I

The upper ferrule 8 is provided with an internal flange 40', which lange40 is formed with an annular shoulder 42 for the reception of the ventcap 43, a second annular shoulder 44 and an upwardly flared or taperedsurface 45. An annular ring 46 mounted upon the shoulder -44 supports anon-conducting washer 48 having a central or axial opening 50', throughwhich the upwardly extending shank of the arcing terminal 25 projects.The terminal 25 is held in its upper set position against the tension orvof the spring by means of a tension or strain wire 108, which passesdiametrically through the shank 109 of theupper terminal 25 and issecured at each end under the heads of suitable screws 112 mount- .ed atdiametrically opposite points in the flared or tapered surface 45. Theupper end of the shank 109 terminates just above the washer 48 and isdrilled axially and` tapped at 114 (Fig. 13) to receive a removablescrew 115 under which the intermediate portion of a fuse link 116 issecured. The link 116 is shown as extending l comprising, in this case,a pluralit at right angles to thestrain wire 108, and the opposite endsof this fuse link 116 .are mechanically and electrically connected tothe ferrule 8 by screws 120 threaded into the sur- ,y face 45 atdiametrically opposite i pointsf a5 -fIhe liquid directing or sprayingmember 121 1s mounted in this case upon the shank 109 by means of threescrews 122, the heads of n which are preferably countersunk in thedirector, as shown.

Vibration of the movable system of this fuse is damped by ananti-vibration device of spring lingers 125. To obtain a simple, eective and inexpensive scheme of formin these fingers and securing themin place, lghave devised the arrangement shown. One pair of lingers isformed of a single length of wire which passes through an opening 126(Fig. 13)V in the shank of the terminal 25 and is then bent around theperiphery of the shank 109, 90 degrees in the particular embodimentshown, and passed through an opening 127 at substantially right anglesor normal to the opening 126.` The other pair of fingers are formed of asimilar length of wire passed through an opening 128, bent around theperiphery of the shank 109, 9 0 degrees, and then passed through anopening 130 substantially l, normal to the opening `128. vvThis providesa also guides the movable working parts of the i fuse, and by dampingthe vibrat1on,relieves the fuse element, strain wire and other parts ofdestructive stresses that might otherwise be imposed.

When the fuse link 116 blows or is melted or fused, the tension wire 108is subjected to a heavy current and to the heat generated by the fusingof the link 116. While it has the mechanical strength for holding thefuse set, it is fused at once by the are and heat generated by theblowing of the fuse 116,'-and releases .the spring 30 -which drawstheupper arcing terminal 25', director 121, and anti-vibration device125 downwardly, the director 121 projecting a stream of thel arcextinguishing liquid 150, contained within the tube 5 as before upon thespace where the are tends to form. As in the previous embodiment,blowing on very heavy overload or short circuit occurs in the explosionchamber above the washer 48 and between it and the vent cap 43. Theresult is, as before, that on short-circuit or very heavy overload, thevent cap 43 blows 0E before any extensive pressure can develop in theglass tube, and breakage of the glass tube is thus avoided. After thestrain wire 108 `has melted, the washer 48 is, as before, also free torise and thus prevents any excessive pressure within the glass tube whenthe arcing terminal is drawn down into the liquid.

I claim mik v1. In a device of the class described, the I i combinationof a tubular casing, a movable system within the casing including amovable terminal member anda coil spring normally under tensionconnected to said terminal member, and means fulcrumed to swing on apart ofthe movable system for dampingv vibration of said movable system.

2. In a device of the class described, the combination of a tubularcasing, a movable system within the casing including a movable terminalmember and a coil spring normally under tension connected to saidterminal member, land means comprising a plurality of arms carried byand fulcrumed to swing on a part of the movable system and cooperablewith the casing for spacing the system therein and damping vibrationthereof.

3. In a device of the class described, the combination of a relativelystationary termina-l, a movable system including a movable. terminalandanti-vibration. means swingably lfulcrumed and operable to dampvibration of the movable system of the device.

4. In a device of the class described,.the combination of a tubularcasing, a movable terminal therein, .and anti-vibration spacer meansswingably fulcrumed on said movable terminal and cooperable with saidcasing for spacing the movablelterminal in the casing and-for dampingvibijation of said terminal.

5. In al device of the class described, the

.39 prongs spaced circumferentially and fulder tension and connected tosaidmovable terminal, and means on the spring and cooperable with thecasing for damping vibration of the spring.

6. In a device of the class described, the combination of a tubularcasing, a movable terminal therein, a coil spring normally under tensionand connected tothe movable terminal member, anti-vibration spacer meanson the movable terminal and cooperable with the casing for spacing themovable terminal and damping vibration thereoi", and a vibrationJdamperorthe spring connected thereto and cooperable lWith the casing.

7., In a device of the class described, the combination of Va tubularcasing, a terminal thereon, a movable terminal in the casing, meanstending to separate said movable terminal from said Erst terminal, acollar carried by the movable terminal, anti-vibration prongs fulcrumedon the collar, and spring means connected to said prongs adj acent oneend and normally contracting them at that end to swin the opposite endsout into cooperation with the tube.

Y 8. In combination, a terminal member, a collar thereon, a plurality ofinsulating crumed on said collar, and springmeans connectmg said prongsat one end and tending to contract them at that end to swing the oppo-ysite ends of the prongs out into expanded position. f

9. Ina device of the'class described, the combination of a tubularcasing, a coil spring therein, a collar surrounding said spring, andstuds mounted in said collar and pr0- jectin at their inner ends intocooperation with t e spring and attheir outer ends into cooperation withthe casing todamp vibration of the spring. I

10. In combination, separable terminal means, means tending to separatesaid terminal means, a fusible conductor electrically connecting saidterminal means, and a nonconductor of greater tensile strength than thefusible conductor mechanicallyconnectedI to restrain said separatingmeans, the conductor being enclosed within the non-con ductor and ledout and wrapped externally on the non-conductor to form a terminalthereof.

11. In combination, separable terminal means, means tending to separatesaid terminal means, a fuse link including a fusible conductorelectrically connecting said terminal means, and a non-conductor ofgreater tensile strength than the` fusible conductor mechanicallyconnected to restrain said separatingmeans, said non-conductor enclosina. portion of the usible conductor and the conductor being led out andwrapped exsaid pins being odset to ternally of the non-conductor to forma terminal for the link.

12. In a device of the class described, the combination of a tubularcasing, a terminal ferrule on said casing, a movable terminal member, acoil spring normally under tension connected to the movable terminalmember, a fuse element electrically connecting the movable terminalmember and the terminal errule and mechanically restraining the spring,said fuse element comprising a fusible link, andra non-conductor ofgreater tensile strength than said link, said link having electricalcontact With the movable terminal and the non-conductor havingmechanical connection therewith, said link also being eX- posed adjacentthe terminal ferrule, and means for connecting the fuse elementelectrically and the non-conductor mechanically to the ferrule.

13. In a device of the class described, theing of theterminal forforcing said pin means out and securing same in cooperation With'thedirector to secure the director upon the terminal.

15. In a device of the class described, the combination of a terminalmember, a conductor connected thereto, a collar thereon, a coil springhaving convolutions Wrapped about said collar, and pin means projectmgradially vfrom the collar between convolutions bf said spring forattaching same to the co1- 16. In a fuse device, a terminal member, aconductor connected to said terminal mem ber,.a collar on said terminalmember, pin means projecting from said collar and an operating springconnected to said collar' by .cooperation with said pin means.

member, a pair of pins projecting from said collar, andan operatingspring connected to Said collar by cooperation With said pins, ermitthreading of the spring into cooperation therewith.

18. In a device of the class described, the

g combination of a tubular casing, a ferrule on the end of said casing,a first shoulder in said ferrule, a separate ring seated on said fittingwithin the end of the ferrule, and

means connected electrically and mechanically between said terminalmember and the i ferrule between the washer andv said vent cap.

19. In a device of the class described, the combination of a tubularcasing, a terminal ferrule on said casing, a movable terminal member inthe casing, a coil spring normally under tension, and connected to themovable terminal, a fuse link connected between the movable terminal andthe ferrule, and an arcing terminal connected to the ferrule andextending along the fuse into position for cooperation with said movableterminal member.

20. In a device of the class described, the combination of a casing,relatively ixed terminal means, a movable terminal in the casing, anormally restrained spring adapted upon release to operate said movabletermi- 24. In a fuse device, a terminal member, a conductor connected tosaid terminal member, pin means projecting from said terminal member,and an operating spring having separated coils threaded onto saidterminal member by cooperation with said pin means.

25. In a device of the class described, the combination of a terminalmember, a conductor connected to said terminal member, pin meansdisposed radially relative said terminal member, and an operating springthreadedly connected to said terminal member and anchored thereto bycooperation with said pin means.

In witness whereof, I hereunto subscribe my name this 22nd day of May,1925.

NICHOLAS J CONRAD.

nal from said relatively fixed terminal means and means for dampingvibration of said spring. y n 2l. In a device of the class described,the combination of a tubular casing, a terminal ferrule on said casing,a'movable terminal member in the casing, normally restrained means 4forseparating the movable terminal p from the ferrule, a fuse linkconnected between the movable terminal and the errule, and an arcingterminal underlying thefuse link and extending into position forcooperation with the movable terminal.

22. In a device of the class described, the

combination of a tubular casing, a movable terminal therein, a liquiddirector on said terminal and a plurality of radial securing elementsengaging thevdirector and entering the terminal for securin the directorthereon, said radial securing e ements having their inner ends separatedalong the center of said terminal member.

23.l VIn a device of the class described, the

`Combination of a tubular casing, a movablel terminal therein, saidterminal having an axial threaded opening, a liquid director on saidterminal, a plurality of radial securing elements engaging the directorand entering the terminal for securing the director thereon, said radialsecuring elements having their inner ends separated along the center ofsaid terminal member, and a stud element threaded into the axialthreaded opening of saidl terminal member, the separation ofthe innerends of the radial securing elements accom-A modating the axial threadedopening and the threaded stud between them.

